A stable, versatile, nonpeptide synthetic peroxidase enzyme mimic will be prepared in the proposed phase I research. The design of the catalyst is based on the well-precedented peroxidase activity of synthetic metalloporphyrins. This catalyst will be readily soluble in organic solvents and will be equipped with functional group handles which will allow aqueous-so lubilizing groups to be attached as well. Conjugation to antibodies and other proteins and to solid phase supports will be demonstrated. The structural aspects of the catalyst have been designed to overcome the limitations of natural peroxidase enzymes by providing better stability, better resistance to inactivation, better resistance to autooxidation, better diffusion characteristics, better accessibility to transduction, and better conjugation features. The improved catalyst will be directly applicable to ELISA and other enzyme-based analytical techniques both as an improved replacement for current reporter peroxidases and as a new innovation to allow organic phase immunoassay development. PROPOSED COMMERCIAL APPLICATION: The proposed catalyst could replace horseradish peroxidase in aqueous ELISA applications. In addition, HBG holds a patent on the use of antibodies in organic phase. Organic phase immunoassay applications utilizing the catalyst would be immediately valuable for detecting environmental contaminants such as polychlorinated aromatics, insecticides, agrochemicals, and others, for which current assay methods are extremely expensive due to labor intensive sample preparation.